1. Field of the Invention
The present invention relates to a magnetic disk manufacturing method and apparatus, a magnetic disk, and a magnetic disk apparatus, and more particularly, to a method and an apparatus suitable for manufacturing magnetic disks with protective films coated thereon or magnetic disks with a multiplicity of solid fine particles electrostatically coated on the surfaces of a disk base plate, a magnetic disk manufactured by the above method and apparatus, as well as a magnetic disk apparatus including such a magnetic disk.
2. Description of the Prior Art
Hitherto, sticking of sputtered disks to magnetic heads has been prevented by forming circumferential texture grooves in a substrate as a base plate of the magnetic disk. These texture grooves simultaneously serve to give the magnetic disk a magnetic anisotropy. Thus, the provision of texture grooves has aimed at both establishment of a magnetic anisotropy and prevention of sticking of disks to heads.
With a higher density and downsizing of magnetic disks, however, flying of magnetic heads at a lower level and an improvement in magnetic characteristics have become important problems. Under this situation, it has been required to make minimum working on a disk base plate only enough to give the magnetic disk a magnetic anisotropy, provide a smooth magnetic film with a constant thickness, and improve magnetic characteristics. When the disk base plate is subjected to minimum working for satisfying the above requirements, roughness of the disk surface is too small to ensure prevention of sticking of disks to heads. This requires that the prevention of sticking be ensured by the surface configuration of a protective film.
To solve the above problem, Japanese Unexamined Patent Publication No. 3-252922 discloses a method of forming a mask on a protective film of a magnetic disk by photolithographic process, and etching the protective film through the mask to form desired projections on the surface of the protective film.
Thus, in the prior art disclosed in Japanese Unexamined Patent Publication No. 3-252922, the desired surface configuration of a magnetic disk is obtained by etching the protective film through the mask formed by the photolithographic process. The disclosed method, however, has problems that the time required for manufacture is long and the use of various chemicals leads to a high possibility of danger.
As a technique for solving the above problems, known is a method of depositing fine solid particles on the surface of a protective film and using the fine solid particles as etching masks. It is easily conceivable to deposit such fine solid particles on the disk surface by spin coating process, spraying process, or dipping process into a suspension. These processes, however, accompany problems of large variations in a particle-deposited area ratio in the disk surface, inability to produce masks of substantially uniform size because of fine particles being likely to agglomerate, and difficulties in washing away the solid particles after etching.